Working together, John and Jack can type 20 pages in one hour.

Working together, John and Jack can type 20 pages in one hour. They will be able to type 22 pages in one hour if Jack increases his typing speed by 25%. What is the ratio of Jack's normal typing speed to that of John?
1/3
2/5
1/2
2/3
3/5











let N = rate of John typing
let K = rate of Jack typing

N + K = 20
N + 1.25*K = 22

Solve the system of equations:
N = 12
K = 8

K/N = 8/12

ANSWER: D. 2/3